I'm convinced it's worth actively discouraging them from participating in LessWrong

Really? From a thread devoted to increasing the diversity of LW you managed to conclude that people with political views sufficiently different from yours should be driven away from the site. Do you want another echo chamber? There are plenty of those on the 'net.

Now would be a good time to re-read Well-Kept Gardens Die By Pacifism in its entirety.

Now would also be a good time to re-read Politics Is the Mind-Killer and ponder on the difference between trolls and people whose political ideas you don't like.